Asymptotic form of the penetration probability of the quantum harmonic oscillator into the classically forbidden region

The penetration probability of the quantum harmonic oscillator into the classically forbidden region is examined in the limit of large quantum numbers using analytical methods. An expression is derived for the asymptotic form of the penetration probability, and is shown to be in good agreement with an earlier result obtained by numerical methods. The asymptotic form of the probability density in the region between the classical turning points is also presented and found to have a simple physical interpretation

Revisiting the statistical specification of near-multicollinearity in the logistic regression model

This paper revisits the statistical specification of near-multicollinearity in the logistic regression model. We argue that the ceteris paribus clause, which assumes that the maximum likelihood estimator of β remains constant as the correlation ( ρ ) between the regressors increases, invoked under the traditional account of near-multicollinearity is rather misleading. We derive the parameters of the logistic regression model and show that they are functions of ρ , indicating that the ceteris paribus clause is unattainable. Monte Carlo simulations confirm these findings and further show that: coefficient estimates and related statistics fluctuate in a non-symmetric, non-monotonic way as | ρ |→1; that the impact of near-multicollinearity is centered on the estimates of β ; and that the impact on substantive inferences does not necessarily follow what the traditional account implies

Intrarailroad and Intermodal Competition Impacts on Railroad Wheat Rates

The issue addressed in this paper is more fully understanding the relationship of intrarailroad competition and rail rates for wheat in the largest wheat producing states, which are Idaho, Kansas, Minnesota, Montana, North Dakota, Oklahoma, South Dakota, Texas, and Washington. The overall objective of the study is to investigate railroad pricing behavior for wheat shipments. The rate model was estimated with OLS in double-log specification utilizing the 2012 STB Confidential Waybill sample and other data.The research found that the distance from origin to destination and the total shipment weight had the expected negative relationships with railroad wheat rates and were statistically significant. The distance from origin to the nearest barge loading location had the expected positive relationship to railroad wheat rates and was also significant. The weight of each covered hopper car and the Herfindahl-Hirschman Index were both non-significant. However, the study used other data to determine that intrarailroad competition for wheat shipments within states appears to be present in most states

Nonlocal effects in dissociative electron attachment to H2

Electron scattering by diatomic molecules involving the formation of a single resonance is treated within the configuration-interaction formalism. A technique is presented for solving the resulting nonlocal integro-differential equation for the nuclear motion in the resonant state. This technique is applied to the scattering of electrons by molecular hydrogen (and its isotopes) via the formation of X^2 Σ^+_u resonance, using a semiempirical model for the resonant state. Numerical cross sections for dissociative attachment, to H_2, of electrons with energies below 5 eV are presented and compared both with available experimental data and with those obtained using the local approximation for the complete integro-differential equation. In contrast to the local theory, the nonlocal theory predicts cross sections that exhibit discontinuities at energies at which a new vibrational channel opens up. We also give an upper bound for attachment cross sections that holds for all isotopes of molecular hydrogen for all values of the incident electron energies

Do Jet Fuel Price Movements Help Forecast Airline Fares and the Demand for Air Travel?

Citation: Bebonchu, A., Bachmeier, L., & Williams C. (2018) Do Jet Fuel Price Movements Help Forecast Airline Fares and the Demand for Air Travel? Unpublished manuscript.The paper studies the predictive content of jet fuel prices for the U.S. aviation industry through in-sample and out-of-sample forecasting exercises. Our results suggest the possibility of limited improvements in the predictions of airline fares, and little evidence of predictability from jet fuel prices to measures of air travel demand

Reference Physiological Ranges for Serum Biochemical Parameters among Healthy Cameroonians to Support HIV Vaccine and Related Clinical Trials

Background: A valid scientific evaluation of the efficacy of HIV vaccines or antiretroviral drugs includes measurement of changes in physiological parameters of subjects from known established baseline reference ranges. This study was designed to establish reference ranges for biochemical parameters among healthy adult Cameroonians to support planned HIV Vaccine clinical trials and scaling up of ARV drugs among AIDS patients.Methods: After informed consent, blood and urine samples were collected from a total of 576 adult Cameroonians and analyzed for the presence of underlying pathologies that may affect biochemical parameters. Samples from 501 of them were found eligible for the determination of reference biochemical parameters. After complete assay, the data were subjected to both parametric and non parametric statistics for analyses with 2.5 and 97.5 percentiles considered as the lower and upper limits of reference ranges.Results: There were 331(66.1%) males and 170(33.9) females, with 359(71.7%) and 142(28.3) of them residing in the urban and rural areas respectively. Statistically significant differences (P<0.05) were observed in the following biochemical parameters between urban and rural participants: AST, ALT, alkaline phosphatase, creatinine, total protein, albumin, triglyceride, total cholesterol, and the bilirubins. When the data were regrouped into sex, there were statistically significant differences (P<0.05) in the following parameters between males and females: AST, ALT, creatinine, albumin, triglyceride, total cholesterol, and direct bilirubin.Conclusion: The present study shows that sex and geographic location have significant impact on reference physiological biochemical parameters of healthy, adult Cameroonians; hence this should be taken into consideration when monitoring participants either during HIV Vaccine clinical trials or on antiretroviral (ARV) drugs treatment.Key Words: Normal Biochemical Ranges, Health Adult Cameroonians

Reference Physiological Ranges for Serum Biochemical Parameters among Healthy Cameroonians to Support HIV Vaccine and Related Clinical Trials

Background: A valid scienti\ufb01c evaluation of the e\ufb03cacy of HIV vaccines or antiretroviral drugs includes measurement of changes in physiological parameters of subjects from known established baseline reference ranges. This study was designed to establish reference ranges for biochemical parameters among healthy adult Cameroonians to support planned HIV Vaccine clinical trials and scaling up of ARV drugs among AIDS patients. Methods: After informed consent, blood and urine samples were collected from a total of 576 adult Cameroonians and analyzed for the presence of underlying pathologies that may a\ufb00ect biochemical parameters. Samples from 501 of them were found eligible for the determination of reference biochemical parameters. After complete assay, the data were subjected to both parametric and non parametric statistics for analyses with 2.5 and 97.5 percentiles considered as the lower and upper limits of reference ranges. Results: There were 331 (66.1%) males and 170 (33.9) females, with 359 (71.7%) and 142 (28.3%) of them residing in the urban and rural areas respectively. Statistically signi\ufb01cant di\ufb00erences (P<0.05) were observed in the following biochemical parameters between urban and rural participants: AST, ALT, alkaline phosphatase, creatinine, total protein, albumin, triglyceride, total cholesterol, and the bilirubins. When the data were regrouped into sex, there were statistically signi\ufb01cant di\ufb00erences (P<0.05) in the following parameters between males and females: AST, ALT, creatinine, albumin, triglyceride, total cholesterol, and direct bilirubin. Conclusion: The present study shows that sex and geographic location have signi\ufb01cant impact on reference physiological biochemical parameters of healthy, adult Cameroonians; hence this should be taken into consideration when monitoring participants either during HIV Vaccine clinical trials or on antiretroviral (ARV) drugs treatment